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Cybersecurity · head to head

Cisco Duo vs Nessus

Cisco Duo logo

Cisco Duo

Cybersecurity

Trusted access for all users, all devices

From
Free
Rated
-
Full reviewWebsite
Nessus logo

Nessus

Cybersecurity

The most trusted vulnerability assessment solution

From
$4790/year
Rated
-
Full reviewWebsite

The short version

  • Only Cisco Duo has a free tier, so it costs nothing to try first.
  • Each has a real cost: Cisco Duo free tier limited to 10 users maximum; Nessus nessus Professional is $4,790 for one year, with no free or low cost commercial tier
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Cisco Duo and Nessus actually diverge.

Attributes where Cisco Duo and Nessus differ
AttributeCisco DuoNessus
Starting priceFree$4790/year
Free tierYesNo
PlatformsWebDesktop, Api
FoundedUnknown2002

Identical on both: pricing model (subscription), user rating (Not yet rated), category (Cybersecurity).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Cisco Duo

Nothing recorded that Nessus does not also cover.

Only in Nessus

  • Vulnerability scanning
  • Configuration auditing
  • Malware detection
  • Web application scanning
  • Cloud scanning
  • Compliance checks
  • Patch auditing
  • Pre-built policies

What people use each for

The jobs each tool is most often brought in to do.

Cisco Duo

  • Eliminating phishing with passwordless authnot Nessus
  • Implementing zero trust with device trustnot Nessus
  • Protecting sessions from hijacking and theftnot Nessus
  • Managing compliance for regulated industriesnot Nessus

Nessus

  • Vulnerability scanning for individual practitionersnot Cisco Duo
  • Enterprise vulnerability managementnot Cisco Duo
  • Web application security assessmentsnot Cisco Duo

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Cisco Duo

  • Free tier limited to 10 users maximum
  • Licenses must be purchased in 10-user increments (under 100 users) or 25-user increments (100+ users)
  • Pricing is per-user per-month with minimum purchase increments

Nessus

  • Nessus Professional is $4,790 for one year, with no free or low cost commercial tier
  • Multi year terms are the only discount route, at $9,330.95 for two years and $13,637.54 for three
  • It is a single user scanner, so team workflows mean migrating to another Tenable product
  • Tenable One vulnerability management is priced separately, starting at $3,500 a year for 100 assets

Pricing, plan by plan

Cisco Duo

Free
  • FreeFree
    • Multi-factor authentication (MFA)
    • Seamless integrations
    • Authenticator app
  • Essentials$3/month
    • All Free features
    • Duo Directory
    • Phishing-resistant MFA
  • Advantage$6/month
    • All Essentials features
    • Identity intelligence
    • Cisco Identity Intelligence (ISPM, ITDR)
  • Premier$9/month
    • All Advantage features
    • Complete device trust
    • VPN-less remote access

Nessus

$4790/year
  • Nessus Professional$4790/year
    • 1 year license
    • Best for individual security professionals
  • Nessus Professional 2-Year$9330.95/2 years
    • 2 year license with discounted rate vs. annual
  • Nessus Professional 3-Year$13637.54/3 years
    • 3 year license with discounted rate vs. annual
  • Nessus Expert$6790/year
    • 1 year license
    • Enhanced capabilities vs. Professional

Which should you pick?

Choose Cisco Duo if

  • You want to start without paying.
Cisco Duo review

Choose Nessus if

  • You need vulnerability scanning.
  • You work on Desktop, Api.
  • You also want configuration auditing.
Nessus review

Questions people ask

Is Cisco Duo or Nessus better?
Neither clearly leads. Cisco Duo starts at Free and Nessus at $4790/year, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cisco Duo or Nessus?
Cisco Duo has a free tier; the other does not. Paid plans start at Free for Cisco Duo and $4790/year for Nessus.
Does Cisco Duo or Nessus run on more platforms?
Cisco Duo runs on Web. Nessus runs on Desktop, Api.
Can I use Cisco Duo for free?
Yes. Cisco Duo has a free tier, so you can try it without paying. Nessus starts at $4790/year.
What is Cisco Duo best used for?
Cisco Duo is most often used for eliminating phishing with passwordless auth, implementing zero trust with device trust, protecting sessions from hijacking and theft, managing compliance for regulated industries. Of those, eliminating phishing with passwordless auth and implementing zero trust with device trust are not what Nessus is typically brought in for.
What can Cisco Duo do that Nessus cannot?
Nessus covers Vulnerability scanning, Configuration auditing, Malware detection, Web application scanning.

Answered from the vendors’ own pages

Cisco Duo: How much does Cisco Duo cost?

Cisco Duo Free is $0/user/month (up to 10 users). Paid plans start at $3/user/month (Essentials), $6/user/month (Advantage), and $9/user/month (Premier). Billing is per-user per-month.

Source
Nessus: What is the cheapest Nessus option?

Nessus Professional starts at $4,790 per year for a 1-year license. Multi-year commitments offer discounts, with 2-year licenses at $9,330.95 and 3-year licenses at $13,637.54.

Source
Cisco Duo: Is Cisco Duo free to try?

Yes, Duo Free offers multi-factor authentication and seamless integrations at $0/user/month for up to 10 users.

Source
Nessus: What is the difference between Nessus Professional and Expert?

Nessus Expert costs $6,790 per year for a 1-year license (compared to $4,790 for Professional) and includes enhanced capabilities. Multi-year rates are available at discounted prices.

Source
Cisco Duo: What is the minimum purchase for Cisco Duo?

Organizations must buy licenses in 10-user increments for under 100 users, or 25-user increments for 100 or more users. Plans are modifiable at any time.

Source
Nessus: Does Nessus offer optional support or training?

Yes, Nessus offers add-on services: Advanced Support at $400/year provides 24x365 access to phone, email, community, and chat support. On-Demand Training costs $275/year for Fundamentals course access or $385/year for both Fundamentals and Advanced courses.

Source
Cisco Duo: What does the Advantage plan add over Essentials?

Advantage ($6/user/month) adds identity intelligence, Cisco Identity Intelligence (ISPM, ITDR), Duo Passport, session theft protection, Active Directory Defense, and risk-based authentication.

Source
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